Low noise oximetry cable

ABSTRACT

The present disclosure includes a cable for a patient monitoring system. The cable can have a flexible and durable overall construction that enables the cable to withstand repeated winding and unwinding and prevent kinks from developing. The cable may include multiple bundles encased in inner jackets that reduce the amount of friction against other cable elements and allows the bundle to move more freely inside an outer jacket of the cable. The multiple bundles may include multiple wires or cords. The cable can include a flexible core that runs through the middle of the cable. The multiple bundles can be twisted, weaved, or untwisted around the core.

RELATED APPLICATIONS

Any and all applications for which a domestic priority claim isidentified in the Application Data Sheet of the present application arehereby incorporated by reference under 37 CFR 1.57.

BACKGROUND Field of the Disclosure

The disclosure relates to improving the performance of patient monitorsthrough low noise cabling.

Description of the Related Art

Oximetry utilizes a noninvasive optical sensor to measure physiologicalparameters of a patient. In general, the sensor has light emittingdiodes (LEDs) that transmit optical radiation into a tissue site and adetector that responds to the intensity of the optical radiation afterabsorption (for example, by transmission or transreflectance) by, forexample, pulsatile arterial blood flowing within the tissue site. Basedon this response, a processor determines measurements for oxygensaturation (SpO₂), pulse rate, plethysmograph waveforms, perfusionquality index (for example, an index that quantifies perfusion),assessments of other blood constituents, parameters or analytes,including for example, a percent value for arterial carbon monoxidesaturation (HbCO), a percent value for methemoglobin saturation (abrownish-red form of hemoglobin that cannot function as an oxygencarrier) (HbMet), total hemoglobin (HbT), fractional SpO₂ (SpaO₂) or thelike.

Additionally, caregivers often desire knowledge of HbO₂, Hb, bloodglucose (HbGu), water, the presence or absence of therapeutic drugs(aspirin, Dapson, nitrates, or the like) or abusive/recreational drugs(methamphetamine, alcohol, steroids, or the like), concentrations ofcarbon dioxide (CO₂), oxygen (O₂), oxygen concentration, pH levels,bilirubin, perfusion quality, albumin, cyanmethemoglobin, andsulfhemoglobin (HbSulf), signal quality or the like.

It is noted that “oximetry” as used herein encompasses its broadordinary meaning known to one of skill in the art, which includes atleast those noninvasive procedures for measuring parameters ofcirculating blood through spectroscopy. Moreover, “plethysmograph” asused herein (commonly referred to as “photoplethysmograph”), encompassesits broad ordinary meaning known to one of skill in the art, whichincludes at least data representative of a change in the absorption ofparticular wavelengths of light as a function of the changes in bodytissue resulting from pulsing blood.

Oximeters capable of reading many of the foregoing parameters duringmotion induced noise are available from Masimo Corporation of Irvine,Calif. Moreover, portable and other oximeters are disclosed in at leastU.S. Pat. Nos. 6,770,028, 6,658,276, 6,157,850, 6,002,952, and5,769,785, which are incorporated by reference herein, and others patentpublications such as those listed at http://www.masimo.com/patents.htm.Such reading through motion oximeters have gained rapid acceptance in awide variety of medical applications, including surgical wards,intensive care and neonatal units, general wards, home care, physicaltraining, and virtually all types of monitoring scenarios.

The detectors of the noninvasive sensors read by many of the foregoingpatient monitors generate one or more low-level signals that aresusceptible to corruption from various noise, such as electromagneticinterference (EMI) and internal noise that originate in the sensor,cabling and monitors. One internal noise source is due to atriboelectric effect, which includes static charges that build when twomaterials rub together. For example, when a cable housing detector wiresis flexed, impacted, or the like, the detector wires may rub togetherand triboelectric noise can be induced in the detector signal. Theseinduced triboelectric noise spikes can be orders of magnitude largerthan the desired low level detector signals.

To alleviate the buildup of triboelectric charges, low noise cablemanufacturers included graphite coatings exterior to, for example, thecabling configured to communicate detector signals. However, thegraphite gel used in the manufacturing process proved difficult to applyand remove. Because of these and other difficulties, manufacturers begansubstituting the graphite coatings with a coextruded conductive PVCsheath around, for example, their sensitive signal carrying cables.

SUMMARY

The present disclosure describes a low noise oximetry cable thatprovides an improved, flexible, and durable overall construction forvarious medical environments. The cable can be particularly useful inenvironments such as emergency medical situations (EMS), where cablescan undergo a tremendous amount of stress, such as repeated winding andunwinding, that can cause kinks to develop leading to or creating anelectrical short in the cables. The construction of the cable describedherein can reduce damage resulting from stress like repeated winding andunwinding and prevent kinks from developing. The cable can be part of apatient monitoring system that transmits real-time patient data toindividual or multiple integrated or non-integrated devices.

The cable can include multiple bundles of conductors. The bundles canevenly distribute stress exerted on the conductors or cords within thecable. The bundles may be wrapped or weaved around a core that isflexible and durable. Some or all of conductors may be assembled twistedor untwisted with one or more cords. The conductors may be assembledtwisted or untwisted around one or more central cores or cords.

An oximetry system is disclosed that can acquire signals indicative ofone or more physiological parameters of a patient. The oximetry systemcan include a noninvasive sensor including a detector configured todetect light attenuated by a body tissue and output a detector signalindicative of the light detected after attenuation by the body tissue.The oximetry system also includes a patient monitor configured toreceive the detector signal and determine one or more physiologicalparameters the patient from the detector signal. The oximetry systemadditionally includes a cable having an outer jacket, an outer shield, afirst bundle including wires, a second bundle including wires, and acore at least partially surrounded by the first bundle and the secondbundle. The outer shield at least partially surrounds the first bundleand the second bundle, and the outer jacket at least partially surroundsthe outer shield.

A cable is disclosed that can transmit signals for an oximetry systemusable to determine of one or more physiological parameters of apatient. The cable can include a first bundle with wires. The cable alsocan include a second bundle with wires. The cable can additionallyinclude a core at least partially surrounded by the first bundle and thesecond bundle.

In some embodiments, an oximetry system is disclosed that can acquiresignals indicative of one or more physiological parameters of a patient.The oximetry system can include a noninvasive sensor, a patient monitor,and a cable. The noninvasive sensor can include a detector configured todetect light attenuated by a body tissue of a patient and output adetector signal indicative of the light detected after attenuation bythe body tissue. The patient monitor can be configured to receive thedetector signal and determine one or more physiological parameters forthe patient from the detector signal. The cable can include an outerjacket, an outer shield, a first bundle, and a second bundle. The firstbundle can include a first plurality of wires. The second bundle caninclude a second plurality of wires. The outer shield can at leastpartially surround the first bundle and the second bundle. The outerjacket can at least partially surround the outer shield.

The oximetry system of the preceding paragraph can include one or moreof the following features: The noninvasive sensor can include a sensorhousing configured to position an emitter and the detector proximate tothe body tissue. The one or more physiological parameters can include anoxygen saturation and a pulse rate. The cable can include a coreconfigured to reduce a tensile stress exerted on the cable and increasea durability of the cable. The core can be flexible. The first bundleand the second bundle can be twisted or weaved around the core. Thefirst bundle can include a first shield at least partially surroundingthe first plurality of wires. The cable can include a third bundle atleast partially surrounded by the outer shield. The third bundle caninclude a third plurality of wires. The first bundle, the second bundle,and the third bundle can be twisted or weaved around a core. The firstbundle and the second bundle may not be concentric with each other. Thecable can include a core, and the first bundle and the second bundle maynot be concentric with the core. The first bundle can include adifferent number of wires than the second bundle. The core can include aplurality of arcuate surfaces that contact the first bundle and thesecond bundle and limit an amount of contact between the first bundleand the second bundle. The plurality of arcuate surfaces can be formedat least partly by pressure from the first bundle and the second bundleon the core.

A method of manufacturing the oximetry system of preceding twoparagraphs is additionally disclosed.

In some embodiments, a cable is disclosed that can transmit signals inan oximetry system. The cable can include a first bundle, a secondbundle, and a core. The first bundle can include a first plurality ofwires. The second bundle can include a second plurality of wires. Thecore can be configured to reduce a tensile stress exerted on the cableand increase a durability of the cable.

The cable of the preceding paragraph can include one or more of thefollowing features: The first bundle and the second bundle can betwisted or weaved around the core. The first bundle can include a firstshield at least partially surrounding the first plurality of wires. Thesecond bundle can include a second shield at least partially surroundingthe second plurality of wires. A third bundle that can be disposedwithin a jacket along with the first bundle and the second bundle. Thefirst bundle and the second bundle may not be concentric with eachother. The first bundle and the second bundle may not be concentric withthe core. The core can define a central axis. The first bundle caninclude a different number of wires than the second bundle.

A method of manufacturing the cable of preceding two paragraphs isadditionally disclosed.

In some embodiments, a method is disclosed for manufacturing a cablethat can transmit signals in an oximetry system. The method can include:assembling a first bundle that can include a first plurality of wires;assembling a second bundle that can include a second plurality of wires;and placing, within a jacket, the first bundle and the second bundleadjacent to a core.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features are discussed herein. It is to be understood that notnecessarily all such aspects, advantages or features will be embodied inany particular embodiment of the invention and an artisan wouldrecognize from the disclosure herein a myriad of combinations of suchaspects, advantages or features.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a patient monitoring system including apatient monitor and a noninvasive optical sensor communicating through acable.

FIG. 2A is a cutaway side-view of the cable of FIG. 1 .

FIG. 2B is a cross-sectional view of the cable of FIG. 1 .

FIG. 2C is a cutaway perspective view of the cable of FIG. 1 .

DETAILED DESCRIPTION Introduction

A low noise oximetry cable is provided that can communicate a low levelsensitive signals between a sensor and a patient monitor. Wires or cordsof the cable can be twisted within individual bundles. The individualbundles can be encased within an inner jacket that can reduce frictionbetween different cable elements. The bundles can be encased at leastpartially by an inner shield that may reduce EMI between the bundles andcrosstalk with other cables.

The bundles can be disposed within an outer jacket and an outer shield.The bundles can wrap around a core. The core can be placed in the centerof the cable and surrounded by the bundles so that the core can absorbstress exerted on the cable and various cable elements. The core can becomposed of a flexible or durable material. Two, three, four, or morebundles can wrap around the core.

A patient monitor usable with the cable disclosed herein is the Root®Platform, a patient monitoring and connectivity platform available fromMasimo Corporation, Irvine, Calif. A mobile physiological parametermonitoring system usable with the cable is described in U.S. Pat. No.9,436,645, issued on Sep. 6, 2016, titled “MEDICAL MONITORING HUB,” thedisclosure of which is hereby incorporated by reference in its entirety.

To facilitate a complete understanding of the disclosure, the remainderof the detailed description references the drawings, wherein likereferences number are references with numerals throughout.

Patient Monitoring System Environment

FIG. 1 illustrates a block diagram of a patient monitoring system 100including a patient monitor 102 and a noninvasive optical sensor 104communicating through a cable 144. The patient monitor 102 can includeone or more processing boards 110 communicating with a host instrument112. The one or more processing boards 110 can include processingcircuitry arranged on one or more printed circuit boards capable ofinstallation into a handheld or other monitor, or capable of beingdistributed as an OEM component for a wide variety of host instrumentsmonitoring a wide variety of patient information. As shown, the one ormore processing boards 110 can include an emitter driving circuit 114, afront end 116, and a microprocessor 118.

The emitter driving circuit 114 can output drive signals to thenoninvasive optical sensor 104. The emitter driving circuit 114 maydrive two (2) or more emitters capable of emitting light at two (2) ormore wavelengths, or it may drive a matrix of eight (8) to sixteen (16)or more emitters capable of emitting light at eight (8) to sixteen (16)or more wavelengths.

The front end 116 can condition the signals, applies gain, convertssignals to digital information, and the like, although any or all of thefunctions of the emitter driving circuit 114 and the front end 116 couldbe performed by other software or hardware components, or by themicroprocessor 118. The microprocessor 118 may include one or morehardware or software components capable of executing instructionsdesigned to control drive signals and to process incoming signal datarelated to the drive signals to determine desired physiologicalparameters of a monitored patient. Such parameters may include one ormore of SpO₂, perfusion quality index, pulse rate, HbCO, HbMet, HbT,SpaO₂, HbO₂, Hb, HbGu, water, the presence or absence of therapeuticdrugs or abusive/recreational drugs, CO₂, O₂, pH levels, bilirubin,albumin, cyanmethemoglobin, and HbSulf, signal quality, signalconfidence measures, trend data on one, some, all, or combinations ofthe foregoing, or the like. Moreover, the microprocessor 118 candetermine when alarm conditions exist for alerting a caregiver to thecurrent condition of the patient.

The host instrument 112 can include a display device 120 capable ofproviding indicia representative of the calculated physiologicalparameters. The host instrument 112 can include virtually any housing,including a handheld or otherwise portable monitor capable of conveyingone or more of the foregoing measured or calculated parameters to acaregiver. The host instrument 112 may include audio or visual alarmsthat alert caregivers that one or more physiological parameters arefalling below or above predetermined safe thresholds, or are trending ina predetermined direction (good or bad). The host instrument 112 mayinclude indications of the confidence a caregiver should have in theconveyed data.

The noninvasive optical sensor 104 can include emitters 122 irradiatinga body tissue 124 with light, and one or more detectors 126 capable ofdetecting the light after attenuation by the body tissue 124. Thenoninvasive optical sensor 104 can also include a temperature sensor130, such as, for example, a thermistor or the like, and a memory device132. The memory device 132 may include any one or more of a wide varietyof memory devices, including an EPROM, an EEPROM, a flash memory, a ROM,a RAM, single wire memories, combinations, or the like. The memorydevice 132 can store some or all of a wide variety data and information,including, for example, information on the type or operation of thesensor, type of patient or body tissue, buyer or manufacturerinformation, sensor characteristics including the number of wavelengthscapable of being emitted, number of emitters, emitter specifications,emitter operational characteristics, emitter drive requirements, historyof the sensor temperature, current, or voltage, demodulation data,calculation mode data, calibration data, software such as scripts,executable code, or the like, sensor electronic elements, sensor lifedata indicating whether some or all sensor components have expired andshould be replaced, encryption information, keys, indexes to keys, theparameters the sensor is intended to measure (for example, HbCO, HbMet,etc.), monitor or algorithm upgrade instructions or data, some or all ofparameter equations, combinations of the same, or the like.

As shown in FIG. 1 , the cable 144 can communicate signals between thenoninvasive optical sensor 104 and the one or more processing boards110. The cable 144 can include one or more conductors including detectorcomposite signal conductor(s) 106, temperature sensor conductor(s) 138,memory device conductor(s) 140, emitter drive signal conductor(s) 142,and the like. An example of the cable 144 is disclosed in U.S. Pat. No.7,919,713, which is incorporated by reference herein.

Low-Noise Cable with Bundles

With reference to FIGS. 2A-2C, a patient cable 200 is disclosed. Thecable 200 can be an example of the cable 144 of FIG. 1 . The cable 200can include an outer jacket 202, a separator 204, an outer shield 206, afirst bundle 260, a second bundle 270, a third bundle 280, and a fourthbundle 290. The bundles 260, 270, 280, 290 can each include cords 230 orwires 220. The bundles 260, 270, 280, 290 can each include one or morecords 230 and one or more wires 220. The wires 220 can each include aconductor 222 encased by an insulator 224. The cable 200 can include acore 210 that is located adjacent to or between the bundles 260, 270,280, 290.

The number of the bundles in the cable 200 can vary. The cable 200 can,for example, include two or three bundles instead of four. The number ofthe bundles in the cable 200 can vary depending upon desired cablethickness, shape, size (such as of an outer diameter), rigidity orflexibility, conductive performance, cost, number of signalstransmitted, or the like.

The bundles 260, 270, 280, 290 can each include one or more of the wires220. The number of the wires 220 in one of the bundles 260, 270, 280,290 can vary depending upon desired bundle thickness, shape, size (suchas outer diameter), rigidity or flexibility, conductive performance,cost, or the like. To give individual of the bundles 260, 270, 280, 290a substantially circular shape while maintaining or improvingtriboelectric drain and substantially improving flexibility, the bundles260, 270, 280, 290 can each include three or four of the wires 220 asshown in FIG. 2B. The bundles 260, 270, 280, 290 can alternatively eachinclude two of the cords 230 and two of the wires 220. The bundles 260,270, 280, 290 can alternatively each include five or more of the wires220 or five or more of the cords 230. The total number of the wires 220and the cords 230 in a given bundle can be more than four, five, six,seven, eight, nine, or ten.

The first bundle 260 can include two of the wires 220 and two of thecords 230, while the second bundle 270 and the fourth bundle 290 mayeach include four wires 220 but no cords 230. Moreover, the third bundle280 may include three wires 220 and no cords 230. The total number ofwires 220 or cords 230 can be the same or vary between one or more ofthe bundles 260, 270, 280, 290.

The cords 230 can each have an outer diameter ranging between about0.015 inches and about 0.03 inches, between about 0.018 inches and about0.028 inches, between about 0.02 inches and about 0.026 inches, betweenabout 0.022 inches and about 0.024 inches, or about 0.015 inches, about0.018 inches, about 0.02 inches, about 0.022 inches, about 0.024 inches,about 0.026 inches, about 0.028 inches, about 0.03 inches, or rangesbetween any two of aforementioned values. The outer diameter of each ofthe cords 230 can be less the about 0.015 inches or greater than about0.03 inches. The cords 230 can each have an outer diameter of about0.015 inches.

The wires 220 can each have an outer diameter ranging between about 0.02inches and about 0.04 inches, between about 0.022 inches and about 0.038inches, between about 0.024 inches and about 0.036 inches, between about0.026 inches and about 0.034 inches, between about 0.028 inches andabout 0.032 inches, or about 0.02 inches, about 0.022 inches, about0.024 inches, about 0.026 inches, about 0.028 inches, about 0.03 inches,about 0.032 inches, about 0.034 inches, about 0.036 inches, about 0.038inches, about 0.04 inches, or ranges between any two of aforementionedvalues. The outer diameter of each of the wires 220 can be less thanabout 0.02 inches or greater than about 0.04 inches. The wires 220 caneach have an outer diameter of about 0.022 inches.

The bundles 260, 270, 280, 290 can each have a circumferential widthranging between about 0.04 inches and about 0.07 inches, about 0.045inches and about 0.065 inches, about 0.05 inches and about 0.06 inches,about 0.054 inches and about 0.056 inches, or about 0.04 inches, about0.045 inches, about 0.05 inches, about 0.055 inches, about 0.06 inches,about 0.065 inches, about 0.07 inches, or ranges between any two ofaforementioned values. The circumferential width of the bundles can eachbe greater than about 0.07 inches or less than about 0.04 inches. Thecircumferential width of each of the bundles 260, 270, 280, 290 can varydepending on the thickness of the wires 220, the thickness of the cords230, or a jacket or shield thickness.

The bundles 260, 270, 280, 290 can each have a central axis. The firstbundle 260 can have a first central axis, while the second bundle 270 asecond central axis, the third bundle 280 a third central axis, and thefourth bundle 290 a fourth central axis. The central axes of the bundles260, 270, 280, 290 can be different. For example, the first central axisof the first bundle 260 is different from the second, third, and fourthcentral axis of the bundles 270, 280, 290. The bundles 260, 270, 280,290 can be placed within the cable 200 such that they are notconcentric.

Some of the bundles of the cable 200 can be grouped together. Forexample, the first bundle 260 and the second bundle 270 can be groupedtogether and encased within an insulator or a separator. Similarly, thethird bundle 280 and the fourth bundle 290 can be grouped together andencased with another insulator or another separator.

The bundles 260, 270, 280, 290 can carry different signals. For example,the wires 220 of the first bundle 260 can transmit signals between thedetectors 126 of the noninvasive optical sensor 104 and the front end116. The wires 220 of the second bundle 270 and the fourth bundle 290can transmit signals between the emitter drivers 114 and the emitters122 of the noninvasive optical sensor 104. The emitters 122 can be alight emitting diode (LED) that has a cathode side and an anode side,where a voltage difference between the cathode side and the anode sidecan facilitate generation of light. The wires 220 of the second bundle270 can transmit signals between the cathode sides of the emitters 122and the emitter driving circuit 114, while the wires 220 of the fourthbundle 290 can transmit signal between the anode sides of the emitters122 and the emitter driving circuit 114. The wires 220 of the thirdbundle 280 can transmit signals between the memory device 132 of thenoninvasive optical sensor 104 and the microprocessor 118 of the patientmonitor 102.

The insulators 224 of the wires 220 can have different colors. Thedifferent colors can denote different signals the wires 220 carry. Forexample, one the insulators 224 that are green can denote one of thewires 220 that carries an input signal for the emitters 122, one of theinsulators 224 that is white can denote one of the wires 220 thatcarries an output signal from the detector 126, one of the insulators224 that is black may indicate that one of the wires 220 that does notcarry any signal, and one of the insulators 224 that is purple or pinkmay indicate one of the wires 220 that carries a signal related to athermometer. The wires 220 having the insulators 224 in different colorscan further assist in a manufacturing process for the cable 200.

The bundles 260, 270, 280, 290 can allow one-way or two-way signaltransmission between the noninvasive optical sensor 104 and the patientmonitor 102. For example, a first of the wires 220 of the first bundle260 can transmit signal to the detectors 126 while a second of the wires220 of the first bundle 260 can receive signal from the detectors 126.In another example, the wires 220 of the second bundle 270 and thefourth bundle 290 can each communicate signals between the cathode/anodesides of the emitters 122 and the emitter driving circuit 114. The wires220 of the third bundle 280 can each communicate signals between thememory device 132 and the microprocessor 118.

The cable 200 can include additional bundles for transmitting additionalpatient sensor data or parameters between the noninvasive optical sensor104 and the patient monitor 102. For example, the noninvasive opticalsensor 104 can include the temperature sensor 130, and the cable 200 caninclude a bundle with one or more of the wires 220 or the cords 230 totransmit signals between the temperature sensor 130 and themicroprocessor 118.

The cords 230 can have a coextruded PVC sheath for reducingtriboelectric noise generated by frictional contact between differentcable elements. The cords 230 may not carry electronic signals. Thecords 230 may drain triboelectric induced charges away from theinsulator 224 as well as or better than the graphite coating and PVCsheath. As with the PVC sheath, grouping of the cords 230 with the wires220 can increase the eventual signal quality output from signalprocessing circuitry, such as, for example, a differential amplifier.For example, use of the cords 230 in a manner that maintains the closephysical proximity of the wires 220 tends to ensure external noiseapplied to the cable 200 is applied substantially equally (or common) toeach of the wires 220. Thus, a differential amplifier (not shown) of thepatient monitor 102 can effectively filter the applied external noisethrough, for example, the amplifier's common mode rejection.

Thus, while potentially exhibiting the same or superior advantageouscharacteristics of the coating or sheath, the cords 230 can be easier tocontrol, cause less rigidity (for example, result in a more flexiblebundle), and provide more straightforward processes during manufacturingthan the coating or sheath. For example, the cords 230 may be simply cutaway at points of connectivity for the wires 220 to circuit substratesor other electrical components. Moreover, the bundles 260, 270, 280, 290can be made with the cords 230 that are hallow or thinner than theforegoing coatings or sheath. For these and other reasons, the cords 230may provide for less expensive manufacturing processes.

The first bundle 260 can include an inner shield 226 and an inner jacket228. The inner shield 226 and the inner jacket 228 can at leastpartially surround the wires 220 or the cords 230 of the first bundle260. The inner shield 226 can advantageously reduce electromagneticinterference (EMI) between each of and crosstalk between the wires 220or the cords 230. The inner shield 226 can be circumferentiallysurrounded by the inner jacket 228. One or more or all of the bundles260, 270, 280, 290 can include the inner shield 226 and the inner jacket228.

The inner shield 226 can be constructed of conductive materials or othersuitable shield materials to meet performance or design objectives.Copper, silver, or other suitable materials can be used as materials forthe inner shield 226. For example, the inner shield 226 can beconstructed using braided copper strands. In another example, the innershield 226 can be constructed using spiral copper strands. The thicknessof the inner shield 226 can also be set to meet design objectives. Theinner shield 226 can range in size from 44 AWG to 40 AWG. For example,the inner shield 226 is 44 AWG, tinned copper, with a ninety percentminimum coverage.

The inner jacket 228 can be designed to meet certain design orperformance objectives. The inner jacket 228 can be constructed out ofthe jacket materials previously disclosed or other suitable materials.For example, the inner jacket 228 can be constructed frompolytetrafluoroethylene, or PFTE, which allows the bundles 260, 270,280, 290 to move more freely within the outer shield 206 with adecreased amount of friction between cable elements (for example,bundles 260, 270, 280, 290, the core 210, and the outer shield 206). Inthis regard, the inner jacket 228 can increase the flexibility of thecable 200 during twisting or kinking motions and prevent kinks fromdeveloping within the cable 200 after repeated use.

The inner jacket 228 can be constructed by layering materials. The innerjacket 228 can be constructed with a single sintered PFTE wrap plus asingle unsintered PFTE wrap or be PVC with a single PFTE wrap. The innerjacket 228 can range in size from 0.001 inches to 0.1 inches. Forexample, the inner jacket 228 ranges in size from 0.002 inches to 0.008inches. In one implementation, the inner jacket 228 is a sintered PFTEfilm that is approximately 0.0012 inches thick and a single layer ofunsintered PFTE film that is approximately 0.004 inches thick.

The core 210 can be positioned between the bundles 260, 270, 280, 290 asshown in FIG. 2A-2C. The bundles 260, 270, 280, 290 can wrapped,twisted, or braided around the core 210 such that the core 210 defines acentral axis of the cable 200. The number of the bundles surrounding orwrapping the core 210 can vary depending upon desired cable thickness,shape, size such as outer diameter, rigidity or flexibility, conductiveperformance, cost, and the like. The bundles 260, 270, 280, 290 can beweaved around the core 210. The core 210 and any one of the bundles 260,270, 280, 290 may or may not share the same axis with another of thebundles 260, 270, 280, 290. The core 210 and any one of the bundles 260,270, 280, 290 may or may not be concentric with respect to one another.

It can be advantageous to have the core 210 define a central axis of thecable 200. When the core 210 defines the central axis of the cable 200,more of the tensile stress on the cable 200 can be placed on the core210 than the wires 220 or cords 230. Therefore, having the core 210 at acenter of the cable 200 can reduce the tensile stress on individualcomponents of the cable 200, including each of the bundles 260, 270,280, 290, and increase the durability of the cable 200. Having the core210 can evenly distribute stresses on the bundles 260, 270, 280, 290,the wires 220, and the cords 230 away from the central axis of the cable200 during a kinking motion. The stress on the bundles 260, 270, 280,290 can be torsional, shear, or tensional stress.

The cross-section of the core 210 can vary. For example, the core 210can have a cross-section that is substantially rectangular, circular,elliptical, or another shape. The cross-sectional dimension or area ofthe core 210 can vary along the length of the core 210. The dimensionsof the core 210 can be substantially the same as the circumferentialwidth of the bundles within the cable 200. The width of the core 210 canbe less than or greater than the circumferential width of one of thebundles 260, 270, 280, 290.

The dimensions of the core 210 can affect the interactions between thebundles 260, 270, 280, 290. For example, if the core 210 has a widthless than the circumferential width of one or more of the bundles 260,270, 280, 290, the core 210 may not prevent the bundles 260, 270, 280,290 from contacting each other. If the core 210 has a width greater thanthe circumferential width of one or more the bundles 260, 270, 280, 290,the core 210 may reduce the amount of or prevent the contact between thebundles 260, 270, 280, 290. The reduction in or prevention of thecontact between the bundles 260, 270, 280, 290 can reduce the amount ofstress or friction generated between the bundles 260, 270, 280, 290.

In some examples, a ratio of the width of the core 210 to thecircumferential width of one of the bundles 260, 270, 280, 290 mayaffect the interactions between the bundles 260, 270, 280, 290. Theratio of the width of the core 210 to the circumferential width of oneof the bundles 260, 270, 280, 290 can be between about 0.3 and about0.7, between about 0.35 and about 0.65, between about 0.4 and about 0.6,between about 0.45 and about 0.55, between about 0.48 and about 0.52, orabout 0.3, about 0.35, about 0.4, about 0.45, about 0.5, about 0.55,about 0.6, about 0.65, about 0.7, or ranges between any two ofaforementioned values. The ratio of the width of the core 210 to thecircumferential width of one of the bundles 260, 270, 280, 290 can begreater than about 0.7 or less than about 0.3. The ratio of the width ofthe core 210 to the circumferential width of one of the bundles 260,270, 280, 290 can vary depending on the size of one or more of thebundles 260, 270, 280, 290, the size of the core 210, the desiredflexibility or rigidity of the cable 200, the number of bundles in thecable 200, or the like.

The core 210 can include arcuate surfaces 212 (which can be concave)that interact with outer surfaces of the inner jacket 228. The arcuatesurfaces 212 of the core 210 can increase the durability of the innerjackets 228 of the bundles 260, 270, 280, 290 and reduce the overalldimension of the cable 200. The interaction between the core 210 and theinner jackets 228 of the bundles 260, 270, 280, 290 (for instance,pressure from the bundles 260, 270, 280, 290 on the core 210) can causethe arcuate surfaces 212 to form on an outer surface of the core 210.The arcuate surfaces 212 of the core 210 can be formed at least frominteraction between the core 210 and the bundles surrounding the core210. The arcuate surfaces 212 may each have cross-sectional shapes thatcorrespond to outer surfaces of one of the bundles 260, 270, 280, 290.The shapes of the arcuate surfaces 212 may be rigid or may changeresponsive to the interaction between the core 210 and one or more ofthe bundles 260, 270, 280, 290. The arcuate surfaces 212 can, asdiscussed herein, reduce the amount of contact between the bundles 260,270, 280, 290 and thereby reduce the amount of friction or stress on thebundles 260, 270, 280, 290. This can increase durability of the bundles260, 270, 280, 290 and the cable 200.

The core 210 can be composed of two or more threads wrapped or weavedaround a single thread. For example, the core 210 is composed of threeor more threads wrapped or weaved around a single thread.

A cross-sectional area of the core 210 of the cable 200 can varydepending on the dimensions of the bundles 260, 270, 280, 290, number ofbundles in the cable 200, diameter of the cable 200, desired rigidity orflexibility, desired durability, cost of manufacturing, conductiveperformance, or the like. The core 210 can have smaller or largercross-sectional area than the bundles.

The cable 200 can include more than one core 210. For example, the cable200 having the bundles 260, 270, 280, 290, as shown in FIG. 2B, caninclude the core 210 in the middle and four additional cores located inspaces formed between two of the four bundles 260, 270, 280, 290 and theouter shield 206. Those four additional cores can reduce the amount offriction between the bundles 260, 270, 280, 290 or between the bundles260, 270, 280, 290 and the outer shield 206, thus increasing durabilityof the bundles 260, 270, 280, 290 and the outer shield 206. Theadditional cores can have cross-sectional areas or dimensions that varyfrom or match that of the core 210. For example, the cross-sectionalareas of the additional cores may be larger than, smaller than, or thesame as that of the core 210.

The core 210 can be made out of materials with high flexibility andtensile strength. For example, the core 210 is made out Kevlar fibers.Placing the core 210 with high flexibility and tensile strength can beadvantageous in providing an overall cable construction that is bothdurable and flexible. The durability and flexibility resulting fromhaving the core 210 in the middle wrapped by bundles 260, 270, 280, 290can be advantageous in emergency medical situations, where medicalassessments and interventions are often made in challenging conditionsfor electrical cables, such as cable 144 in FIG. 1 .

Placing the separator 204 between the outer shield 206 and the outerjacket 202 can be advantageous because it can allow the entireconstruction (for example, the bundles 260, 270, 280, 290, the core 210,and the outer shield 206) to be more flexible or move freely inside theouter jacket 202 itself. In addition, this configuration can preventextruded plastic from the outer jacket 202 from penetrating the braidsof the outer shield 206. The separator 204 can be made out of materialswith high flexibility, chemical resistance, thermal resistance, orelectrical resistance. For example, the separator 204 can be made out ofpolytetrafluoroethylene (PTFE).

The outer shield 206, like the inner shield 226, can reduce EMI betweenthe bundles 260, 270, 280, 290 and with other cables. The outer shield206 can be composed of braided, tinned copper stranding or braidedtinsel-wire stranding, where tinsel-wire is produced by wrapping serverstrands of thin metal foil around a flexible nylon or textile core.Because the thickness of the foil may be relatively thin, a bend radiusimposed on the thin metal foil can be much greater than the thickness ofthe foil. In this regard, tinsel-wire can have a low probability ofmetal fatigue and, if used, can provide high tensile strength withoutimpairing flexibility.

The outer jacket 202 can be made out of one or more materials havinghigh flexibility, chemical resistance, high tensile strength, high cutresistance, or elongation properties. Such properties can providegreater protection from kinking and bending due to material properties.For example, the outer jacket 202 can be made out of thermoplasticpolyurethane. The outer jacket 202 can have a thickness ranging betweenabout 0.018″ and about 0.040″, between about 0.02″ and about 0.038″,between about 0.022″ and about 0.036″, between about 0.024″ and about0.034″, between about 0.026″ and about 0.032″, between about 0.028″ andabout 0.030″, or about 0.018″, about 0.020″, about 0.022″, about 0.024″,about 0.026″, about 0.028″, about 0.030″, about 0.032″, about 0.034″,about 0.035″, about 0.036″, about 0.038″, about 0.040″, or rangesbetween any two of aforementioned values. The thickness of the outerjacket 202 can be less than 0.018″ or greater than about 0.040″.

The cable 200 can have an outer diameter ranging between about 0.1″ andabout 0.4″, between about 0.125″ and about 0.375″, between about 0.15″and about 0.35″, between about 0.175″ and about 0.325″, between about0.2″ and about 0.3″, between about 0.225″ and about 0.275″, or about0.1″, about 0.125″, about 0.15″, about 0.175″, about 0.2″, about 0.225″,about 0.235″, about 0.25″, about 0.275″, about 0.3″, about 0.325″, about0.35″, about 0.375″, about 0.4″, or ranges between any two ofaforementioned values. The outer diameter of the cable 200 can be lessthan 0.125″ or greater than about 0.40″.

Terminology

The following description is merely illustrative in nature and is in noway intended to limit the disclosure, its application, or uses. Forpurposes of clarity, the same reference numbers will be used in thedrawings to identify similar elements. It should be understood thatsteps within a method may be executed in different order withoutaltering the principles of the present disclosure.

Conditional language used herein, such as, among others, “can,” “might,”“may,” “for example,” and the like, unless specifically statedotherwise, or otherwise understood within the context as used, isgenerally intended to convey that certain embodiments include, whileother embodiments do not include, certain features, elements or states.Thus, such conditional language is not generally intended to imply thatfeatures, elements or states are in any way required for one or moreembodiments or that one or more embodiments necessarily include logicfor deciding, with or without author input or prompting, whether thesefeatures, elements or states are included or are to be performed in anyparticular embodiment. The terms “comprising,” “including,” “having,”and the like are synonymous and are used inclusively, in an open-endedfashion, and do not exclude additional elements, features, acts,operations, and so forth. Also, the term “or” is used in its inclusivesense (and not in its exclusive sense) so that when used, for example,to connect a list of elements, the term “or” means one, some, or all ofthe elements in the list. Further, the term “each,” as used herein, inaddition to having its ordinary meaning, can mean any subset of a set ofelements to which the term “each” is applied.

Terms such as “substantially,” “about,” “approximately” or the like asused in referring to a relationship between two objects is intended toreflect not only an exact relationship but also variances in thatrelationship that may be due to various factors such as the effects ofenvironmental conditions, common error tolerances, manufacturingvariances, or the like. It should further be understood that althoughsome values or other relationships may be expressed herein without amodifier, these values or other relationships may also be exact or mayinclude a degree of variation due to various factors such as the effectsof environmental conditions, common error tolerances, or the like. Forexample, when referring to measurements, about a specified measurementcan, in some contexts, refer to a measurement variation of around equalto or less than ±10%, ±5%, ±2%, or ±1% (such as a variation of ±10%,±5%, ±2%, ±1%, ±0.8%, ±0.5%, or ±0.3%) from the specified measurement.

Although the low noise oximetry cable including cords is disclosed withreference to few various examples, the disclosure is not intended to belimited thereby. For example, the cords may not be hollow, may include aconductor or other conductive materials, may include only conductors ofany suitably flexible material. Moreover, use of blank hollow cords mayadvantageously apply flexibility in a wide variety of applications,including cabling for virtually any medically monitored signals such asthose invasively or noninvasively acquired signals relating to heart orbrain activity or condition, spinal activity or condition, circulationparameters, tissue health, or the like. Moreover, the cabling mayinclude only one or more portions of the communication link betweensensor components and monitor electronics. The cable may also be anintegral part of a reusable, disposable or combination sensor. Moreover,the addition of cords for shielding sensitive cabling may advantageouslybe applied generally to any and all cabling environments, andparticularly in environments susceptible to triboelectric noise.

Additionally, other combinations, omissions, substitutions andmodifications will be apparent to the skilled artisan in view of thedisclosure herein. Accordingly, the present disclosure is not intendedto be limited by the examples, but is to be defined by reference to theappended claims.

Additionally, all publications, patents, and patent applicationsmentioned in this specification are herein incorporated by reference tothe same extent as if each individual publication, patent, or patentapplication was specifically and individually indicated to beincorporated by reference.

1-20. (canceled)
 21. A cable comprising: a first bundle comprising afirst plurality of wires, a first jacket at least partially surroundingthe first plurality of wires, and an inner shield at least partiallysurrounding the first plurality of wires, the inner shield beingconfigured to provide electromagnetic interference protection; a secondbundle comprising a second plurality of wires and a second jacket atleast partially surrounding the second plurality of wires, the secondjacket being adjacent to and in contact with the first jacket; a thirdbundle comprising a third plurality of wires and a third jacket at leastpartially surrounding the third plurality of wires, the third jacketbeing adjacent to and in contact with the second jacket; a corecomprising a plurality of fibers, the core being adjacent to and incontact with the first jacket, the second jacket, and the third jacket;and an outer jacket at least partially surrounding the first bundle, thesecond bundle, the third bundle, and the core.
 22. The cable of claim21, further comprising a fourth bundle, the fourth bundle comprising afourth plurality of wires and a fourth jacket at least partiallysurrounding the fourth plurality of wires, the fourth jacket beingadjacent to and in contact with the third jacket and the core.
 23. Thecable of claim 22, wherein the fourth bundle is adjacent to and incontact with the first jacket.
 24. The cable of claim 21, wherein thecore is flexible and configured to reduce a tensile stress exerted onthe first bundle, the second bundle, and the third bundle.
 25. The cableof claim 24, wherein the first bundle, the second bundle, and the thirdbundle are twisted or weaved around the core.
 26. The cable of claim 21,wherein the inner shield comprises a metal.
 27. The cable of claim 26,wherein the metal comprises a copper or a silver.
 28. The cable of claim21, wherein the first bundle comprises a different number of wires thanthe second bundle.
 29. The cable of claim 28, wherein the first bundlecomprises a different number of wires than the second bundle and thethird bundle.
 30. The cable of claim 21, wherein the core comprises aplurality of arcuate surfaces that contact the first bundle, the secondbundle, and the third bundle.
 31. The cable of claim 30, wherein theplurality of arcuate surfaces are formed at least partly by pressurefrom the first bundle, the second bundle, and the third bundle on thecore.
 32. The cable of claim 21, wherein the core defines a central axisfor the outer jacket.
 33. The cable of claim 21, wherein none of thefirst bundle, the second bundle, or the third bundle are concentric withthe core.
 34. The cable of claim 21, further comprising an outer shieldat least partially surrounding the first bundle, the second bundle, andthe third bundle and configured to provide electromagnetic interferenceprotection.
 35. The cable of claim 21, in combination with a noninvasivesensor and a patient monitor, the noninvasive sensor comprising adetector configured to detect light attenuated by a body tissue of apatient and output a detector signal indicative of the light detectedafter attenuation by the body tissue, the patient monitor beingconfigured to receive the detector signal and determine one or morephysiological parameters for the patient from the detector signal. 36.The cable of claim 35, in combination with the noninvasive sensor andthe patient monitor, wherein the noninvasive sensor comprises a sensorhousing configured to position an emitter and the detector proximate tothe body tissue.
 37. The cable of claim 36, in combination with thenoninvasive sensor and the patient monitor, wherein the one or morephysiological parameters comprise an oxygen saturation.
 38. A method ofmanufacturing a cable, the method comprising: assembling a first bundlecomprising a first plurality of wires, a first jacket at least partiallysurrounding the first plurality of wires, and an first shield at leastpartially surrounding the first plurality of wires, the first shieldbeing configured to provide electromagnetic interference protection;assembling a second bundle comprising a second plurality of wires and asecond jacket at least partially surrounding the second plurality ofwires; assembling a third bundle comprising a third plurality of wiresand a third jacket at least partially surrounding the third plurality ofwires; and placing the first bundle, the second bundle, and the thirdbundle within an outer jacket so that (i) the first jacket is adjacentto and in contact with the second jacket and a core (ii) the secondjacket is adjacent to and in contact with the third jacket and the core,the core comprising a plurality of fibers.
 39. The method of claim 38,further comprising: assembling a fourth bundle comprising a fourthplurality of wires and a fourth jacket at least partially surroundingthe fourth plurality of wires; and placing the fourth jacket within theouter jacket so that the fourth jacket is adjacent to and in contactwith the first jacket, the third jacket, and the core.
 40. The method ofclaim 38, further comprising twisting or weaving the first bundle, thesecond bundle, and the third bundle around the core.